Hi everyone, My wife's new Dell D531 laptop is acting really slow most of the time, so I installed SpeedSwitch XP. I found out the following: - When you boot on battery, the CPU will run at 800MHz and will stay there no matter what programs you run. - When you boot on AC, the CPU will run at 2GHz most of the time. half of the time it will still run at 800MHz, but a restart will then bring it to 2GHZ. Again, when it runs on 800MHZ, it will stay on that speed until you reboot, when it runs on 2GHz it will stay on that speed, even with Speedstep enabled in the BIOS. In both cases, SpeedSwitchXP is able to detect CPU speed, but it cannot be used to change the speed. Setting Max. Performance when on 800MHz will not bring the speed up. Setting Max. Battery when on 2GHZ will not bring it down. I went into the BIOS and tried enabling/disabling the Speedstep setting, but the results were the same. Even with Speedstep off, it will often run at only 800MHz. I downloaded and installed the latest BIOS from Dell, but that didn't help either. What could be going on here? I am starting to think that the HW is broken in some way.... Any solution that would make the CPU run at the high speed is welcome. regards, Sander

"What could be going on here?" Sounds like it's working as it should. Laptops are designed to vary the CPU speed based on load....this keeps the CPU temp down & the battery life up. If your CPU ran at 2.0GHz at all times, you'd be charging the battery every hour. However, when it's plugged into a power source, battery life isn't an issue so the CPU will run at full speed. Assuming you have an Intel CPU, the technology used is called SpeedStep. If you have an AMD CPU, it's called Cool 'n' Quiet. http://en.wikipedia.org/wiki/SpeedStep